**Abstract**

The whitefly, *Bemisia tabaci* (Gennadius) is a polyphagous pest causing considerable yield loss to many crops around the globe. It is a phloem feeder and transmits several viral diseases as well. It has great genetic diversity and is considered a complex of biotypes. Despite the adoption of several available control strategies, management by chemical pesticides has still been the first choice for the farmers to protect their crops. However, prolonged use of chemical pesticides has ultimately accelerated the development of multifold resistance against various groups of insecticides in different parts of the world. The status of development of insecticide resistance against different groups of insecticides by this pest, mechanisms of resistance, cross-resistance, role of detoxifying enzymes, and management issues have been discussed in this chapter.

**Keywords:** *Bemisia tabaci*, biotype, insecticide resistance, cross-resistance, IRM
